IMPORTANT NOTICEThis judgment was delivered in private. The judge has given leave for this version of the judgment to be published on condition that (irrespective of what is contained in the judgment) in any published version of the judgment the anonymity of the persons concerned must be strictly preserved. All persons, including representatives of the media, must ensure that this condition is strictly complied with. Failure to do so will be a contempt of court.Mr Justice Peter Jackson:1. This judgment concerns expert evidence in family proceedings relating to (i) the capacity of a witness to give evidence and (ii) the witness's veracity.

2. It arises from a fact-finding hearing in proceedings in which two children alleged that they had been sexually abused by their stepfather. The children, then aged 16 and 15, had taken part in some four hours of interviews under the Achieving Best Evidence procedure. At an early case management hearing, the stepfather applied for what was variously described as a "veracity assessment" or "validation exercise" and an assessment of the children's ability to give evidence. That application, which was supported by the other parties, was granted. The court recorded that the report was necessary because serious allegations had been made by the children and because "the court requires assistance with regard to the veracity of their detailed ABE interviews and their capacity to give evidence". The cost of the report was to be shared equally between the parties, with the children's solicitor taking the lead.

3. At the time of the application, transcripts of the ABE interviews were not yet available and with one exception no one in the family proceedings had viewed the DVDs. Nor had a decision been taken about whether the children would give evidence.

4. As a result of the order, instructions were sent to an experienced clinical psychologist with special experience in the analysis of forensic interviews. His report was a careful piece of work. It surveyed material arising before the children's interviews, gave a detailed analysis of the interviews themselves and made reference to research literature. The analysis discussed the quality of the investigation, the significance of retractions, the possibility of collusion and other similar matters of interpretation. The reporter considered and dismissed the possibility that he should interview the children himself. He concluded: "I have seen nothing to suggest that what these children say requires interpretations by an expert, beyond the accommodation of the factors identified in this report. I hope that I have set out the significant factors and possibilities in this case in such a way that weight can be placed on relevant factors, including any new information that emerges."

5. No criticism could possibly be directed at the expert, who carried out the task that the court commissioned in a professional manner. The question that instead arises is whether the assessment should have been commissioned in the first place.

Capacity assessments 6. These children are articulate teenagers. No one ever suggested that they were incapable of giving evidence, though subsequently the older child was understandably reluctant to do so. At a later Re W hearing, I directed that the children should give evidence by video-link, and thereafter ground rules about the nature and scope of the questioning were agreed by the parties and approved by the court. That process was not materially informed by the expert report.

7. An assessment of capacity to give evidence, and the arrangements that should be made to assist a witness to do so fairly, is a proper subject for expert advice where necessary. There will be cases involving young witnesses or witnesses with special characteristics or vulnerabilities where such advice will be important for case management and for ensuring that the witness's evidence is fairly received. Understanding in this field has rapidly advanced in both the criminal and the family courts over recent years. For example, in the present case, where it was suspected that the mother might have some learning disabilities, a focussed psychological report was of assistance in receiving and assessing her evidence.

8. But such advice is obviously not necessary in every case. Here there was ample information already available to the court to safeguard the children's interests and the overall fairness of the process. The children's social worker knew them well enough to form a view. The parties were represented by experienced legal teams, albeit leading counsel had not yet been instructed. The younger child had a Children's Guardian. With this range of professional involvement, the court was in a good position to identify the needs of the situation. The instruction of a psychologist on the issue of capacity was unnecessary, at least at that stage, and as such there was no basis for permitting it.

Veracity assessments / validation exercises9. Having received short submissions from the parties and having consulted the current experience of colleagues, I believe that three principles can be identified:

1) As a matter of law, there is no bar on the admission of expert evidence about whether evidence is or is not likely to be true. That was the conclusion of the Court of Appeal in Re M and R (Child Abuse: Evidence) [1996] 2 FLR 195, interpreting Section 3 of the Civil Evidence Act 1972. It held that expert evidence dealing with issues, including the ultimate issue, was admissible, subject to the overriding requirement of relevance, which, together with questions of weight, was a matter for the judge. At page 210, Butler-Sloss LJ said: "The modern view is to regulate such matters by way of weight, rather than admissibility. But when the judge is of the opinion that the witness's expertise is still required to assist him to answer the ultimate questions (including, where appropriate, credibility) then the judge can safely and gratefully rely on such evidence, while never losing sight of the fact that the final decision is for him."

2) The Court of Appeal left open the question of whether and to what extent the court had a power to exclude evidence that was admissible and potentially relevant. That question has now been answered by FPR 2010 Rule 25.4 which dictates that expert evidence can only be adduced if it is necessary to assist the court to resolve the proceedings. The fact that expert evidence is admissible and might be relevant or even helpful in a general way is not enough.

3) In my view, cases in which it will be necessary to seek expert evidence of this sort will nowadays be rare. While the decision must rest on the facts of the individual case, judicial awareness of these issues has greatly increased, from the Cleveland Inquiry in 1987 to the most recent iteration of the principles of Achieving Best Evidence in 2011. In the two decades since Re M and R (above), understanding has naturally moved on. The process continues to evolve, with the final report of the Children and Vulnerable Witnesses Working Group set up in 2014 by the President of the Family Division expected shortly. The overall result is that judges have been trained in and are expected to be familiar with the assessment of evidence of this kind. The court is only likely to be persuaded that it needs expert advice if it concludes that its ability to interpret the evidence might otherwise be inadequate.

10. I note that in D v B & Others [2006] EWHC 2987 (Fam), Mr Stephen (now HHJ) Wildblood QC said that "Personally I find veracity evidence of assistance in many cases in this field of exceptional difficulty." In that case, matters had gone awry after the veracity expert went far beyond her proper remit and then changed her opinion after leaving the witness box. It might be seen as an extreme illustration of the potential pitfalls of admitting evidence of this kind.

"… this case has, to my mind, demonstrated that veracity or validity assessments have a limited role to play in family proceedings. They are, so far as I am aware, unused in criminal proceedings in this country, and I see strong arguments for imposing restrictions on their use in family cases as well. … there is a danger that some courts, faced with these difficult decisions, will subconsciously defer to the apparent expert. That danger has been recognised in a number of cases in which the courts have emphasised the discrete roles of the expert and the court. In the case of the veracity expert, the danger is particularly acute. The ultimate judge of veracity, i.e. where the truth lies, is the judge and the judge alone. He cannot delegate that decision to any expert. I acknowledge that a child psychiatrist… may be able to point out some features of a child's account that add or detract from authenticity... But, in my experience, many of these features should be obvious to judges in any event. No expert, however experienced and however well briefed about the case, will be in a position to say where the truth lies. Only the judge sees and hears all the evidence."

12. I entirely agree with that statement of principle. I acknowledge that judges, however experienced, benefit from the knowledge that experts bring, but that knowledge can be absorbed through judicial training and awareness of the well-known protocols of good practice; it does not have to be imparted case by case with the attendant expense that is bound to arise.

13. In the present case, the parties now accept that the children's evidence should have been studied before the question of a 'veracity' or 'validation' assessment was considered, and that if that course had been taken, it is unlikely that the application would have been made, let alone granted. I agree. In the event, the parties did not refer to the resulting report during the fact-finding hearing, nor did I do so when determining the veracity of the children's allegations.___________________